09-14-2015, 10:08 PM
Lew Zealand wrote:
As an different example, USB3 will not let me run a 3440x1440 monitor on a 2011 or 2012 Mac at a reasonable refresh rate - 50Hz. In fact it won't do any refresh rate at all but Thunderbolt does. On these machines, you can run 3440x1440 at 30Hz with Displayport but no higher. TB enables the bandwidth to make this monitor usable.
That said, I bought a 2012 2.6 quad mini refurb to replace a 2011 2.0 quad mini refurb for equal parts USB3 and faster cpu. 2011 should have been USB3 but was USB2 only. Lame.
USB 3.0 is not a proper display output. I would never compare the two. You could compare DisplayPort, VGA, DVI, HDMI, and Thunderbolt. I've noticed a lot of Apple systems have a port that's technically capable of higher resolutions and refresh rates, but the GPU can't handle that capability off all outputs. Someone was just posting about this recently with an older Mac, 2009 or 2010 model perhaps? In your case, you might be right,
Thunderbolt might have more bandwidth than DisplayPort 1.2. Can anyone do the math to push 4K at 50 or 60Hz? DisplayPort 1.2 can handle up to four lanes, 5.4Gbps per lane. How does the GPU and associated connections function on those Macs? If Thunderbolt wasn't present, could those Macs have been given more lanes on DisplayPort? I have no idea.